JP2017168778A - Cooling structure of electrolytic capacitor and electrolytic capacitor unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cooling structure of an electrolytic capacitor and an electrolytic capacitor unit capable of improving heat radiation.SOLUTION: An electrolytic capacitor including heat radiation resin having a first surface, and a plurality of electrolytic capacitors which are provided integrally with the heat radiation resin, each of the electrolytic capacitors having an explosion-proof valve, and arranged with the explosion proof valves on the first surface side, and a heat radiation member which has a second surface and is fitted so that the second surface is in thermal contact with the first surface, at least one of the first surface and the second surface is provided with a ventilation path for venting all of the plurality of explosion-proof valves to the outside air, and the ventilation path has a ventilation groove for venting at least one explosion-proof valve of the plurality of explosion-proof valves to the outside air through at least another one of the explosion-proof valves.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an electrolytic capacitor cooling structure and an electrolytic capacitor unit.

  For example, a plurality of electrolytic capacitors having a large capacitance are used in a charger that is mounted on an electric vehicle and converts large power.

  Electrolytic capacitors generate heat due to internal resistance. Moreover, the lifetime of an electrolytic capacitor is shortened at high temperatures according to Arrhenius' law. In order to extend the life, it is important to improve the heat dissipation of the electrolytic capacitor.

In order to improve heat dissipation, there is a method in which the electrolytic capacitor is integrally molded with heat dissipation resin.
For example, Patent Document 1 discloses a structure in which a plurality of electrolytic capacitors are integrated with a heat-dissipating resin.

  However, in such a resin-integrated electrolytic capacitor (hereinafter referred to as an electrolytic capacitor unit), since the resin closes the explosion-proof valve of the electrolytic capacitor, the internal pressure of the electrolytic capacitor increases, and the explosion-proof valve expands. There is a risk of cracking.

  For example, Patent Document 2 discloses a structure in which a vent hole for venting an explosion-proof valve to the outside air is provided in a resin so as not to cause a crack.

  Furthermore, there is a cooling structure for an electrolytic capacitor in which a heat sink having excellent heat transfer characteristics and a resin are brought into contact with each other. In this cooling structure, in order to improve heat dissipation, the contact area between the resin and the heat sink (also referred to as heat dissipation area) is made as wide as possible.

JP-A-4-40267 JP 59-117134 A

  However, when the resin provided with the vent hole disclosed in Patent Document 2 and the above heat sink are brought into contact with each other, the heat sink blocks the vent hole, so that the explosion-proof valve expands and the resin may crack. There was a problem that there was.

  An object of the present invention is to provide an electrolytic capacitor cooling structure and an electrolytic capacitor unit capable of improving heat dissipation.

In order to achieve the above object, the electrolytic capacitor cooling structure according to the present invention comprises:
A heat-dissipating resin having a first surface, and a plurality of electrolytic capacitors provided integrally with the heat-dissipating resin, having an explosion-proof valve and arranged with the explosion-proof valve on the first surface side. Electrolytic capacitor unit,
A heat dissipating member comprising a second surface and attached to the first surface in thermal contact with the second surface;
With
A ventilation path is provided on at least one of the first surface and the second surface to allow all of the plurality of explosion-proof valves to vent to the outside air,
The ventilation path has a ventilation groove that allows at least one explosion-proof valve of the plurality of explosion-proof valves to vent to the outside air via at least one other explosion-proof valve.

The electrolytic capacitor unit according to the present invention is
A heat dissipating resin with a contact surface that is in thermal contact with the heat dissipating destination;
A plurality of capacitors provided integrally with the heat-dissipating resin, having an explosion-proof valve, and arranged on the contact surface side of the explosion-proof valve;
With
Provided on the contact surface a ventilation path for venting all of the plurality of explosion-proof valves to the outside air,
The ventilation path has a ventilation groove that allows at least one explosion-proof valve of the plurality of explosion-proof valves to vent to the outside air via at least one other explosion-proof valve.

  According to the present invention, all of the plurality of explosion-proof valves are vented to the outside air. This prevents the resin from cracking even if the explosion-proof valve expands. Further, a ventilation groove is provided on the contact surface between the resin and the heat dissipating member so that at least one explosion-proof valve is vented to the outside air via the other at least one explosion-proof valve. As a result, the length of the ventilation groove can be shortened compared to the case where a ventilation groove is provided for each explosion-proof valve, and the contact area between the resin and the heat sink is widened to improve heat dissipation. Can be made.

It is a perspective view of the cooling structure of the electrolytic capacitor which concerns on embodiment of this invention. It is sectional drawing of the cooling structure of an electrolytic capacitor. It is a perspective view of an electrolytic capacitor unit when viewed from obliquely above with the lower surface (first surface) of the resin facing upward. It is a figure which shows an example of the ventilation path | route provided in the 1st surface of resin. It is a figure which shows the modification 1 of a ventilation path. It is a figure which shows the modification 2 of a ventilation path. It is a figure which shows the modification 3 of a ventilation path.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a perspective view of a cooling structure 1 for an electrolytic capacitor according to an embodiment of the present invention. FIG. 2 is a cross-sectional view of the electrolytic capacitor cooling structure 1. In FIG. 1 and FIG. 2, the shape and the like of the electrolytic capacitor unit 2 are simplified for easy understanding of the explanation of the electrolytic capacitor cooling structure 1.

  As shown in FIGS. 1 and 2, the electrolytic capacitor cooling structure 1 includes an electrolytic capacitor unit 2, a substrate 3, and a heat sink 4. The electrolytic capacitor unit 2 is disposed so as to be sandwiched from both sides by the substrate 3 and the heat sink 4. In the following description, a direction from the heat sink 4 toward the substrate 3 is referred to as an upward direction, and a direction from the substrate 3 toward the heat sink 4 is referred to as a downward direction.

  The electrolytic capacitor unit 2 includes a plurality of electrolytic capacitors 5 and a heat-dissipating resin 6.

  The substrate 3 has a pilot hole for passing a terminal 51 (described later) of the electrolytic capacitor 5. The substrate 3 also has a pilot hole for passing through a resin pin 53 (described later) of the resin 6. Further, the substrate 3 has a pilot hole through which a fastening screw 33 for fastening the substrate 3 is passed through an upper surface 42 (described later) of the heat sink 4.

  The heat sink 4 is made of a metal such as aluminum, iron, or copper having excellent heat transfer characteristics, and has an upper surface 42 and fins 44. The electrolytic capacitor unit 2 is assembled to the heat sink 4 so that the upper surface 42 of the heat sink 4 is in thermal contact with the lower surface 64 (described later) of the resin 6. The heat sink 4 corresponds to the “heat dissipating member” of the present invention. Further, the upper surface 42 of the heat sink 4 corresponds to the “second surface” of the present invention. Note that “thermal contact” includes direct and indirect contact. As an indirect contact mode, for example, a material (not shown) having excellent heat dissipation properties such as grease and a sheet is provided in the gap between the upper surface 42 of the heat sink 4 and the lower surface 64 of the resin 6.

  The electrolytic capacitor 5 has a terminal 51. The terminal 51 is connected to the substrate 3. In the following description, in the substrate 3, a region connected to the terminal 51 is referred to as a first region 31, and a region excluding the first region 31 is referred to as a second region 32.

  The electrolytic capacitor 5 has an explosion-proof valve V (see FIGS. 2 and 3). The electrolytic capacitors 5 are arranged with the explosion-proof valve V as a lower surface 64 (described later). The plurality of electrolytic capacitors 5 are provided integrally with the resin 6.

  The resin 6 has a cubic shape and includes an upper surface 62, a lower surface 64, and an outer peripheral surface 66. As the material of the resin 6, for example, an acrylic polyurethane resin, a silicone resin, an epoxy mixed resin composition, or the like is used as a heat radiating resin.

  Resin pins 53 are erected on the upper surface 62. A pilot hole is provided in the second region 32 of the substrate 3. Then, the resin pin 53 passed through the prepared hole is fixed with an adhesive. Thereby, the resin 6 can be fixed to the second region 32 of the substrate 3. The resin 6 may be fixed to the second region 32 of the substrate 3 with screws.

  On both sides of the outer peripheral surface 66, flanges 67 are provided so as to protrude in a direction orthogonal to the vertical direction. The flange 67 is screwed to the heat sink 4. Thereby, the resin 6 is fixed to the heat sink 4.

  FIG. 3 is a perspective view of the electrolytic capacitor unit 2 when viewed from obliquely above with the lower surface 64 of the resin 6 facing upward. FIG. 4 is a diagram illustrating an example of the ventilation path 8 provided on the lower surface 64 of the resin 6.

  As shown in FIGS. 2 to 4, a ventilation path 8 is provided on the lower surface 64 of the resin 6. The ventilation path 8 has a plurality of openings 7 and a plurality of ventilation grooves 81. The opening 7 is provided corresponding to the explosion-proof valve V. The lower surface 64 of the resin 6 corresponds to the “first surface” of the present invention.

  The plurality of electrolytic capacitors 5 are arranged in a 3 × 3 matrix, for example. FIG. 2 shows the explosion-proof valve V of the electrolytic capacitor 5.

  The ventilation groove 81 allows all of the explosion-proof valves V to vent to the outside air through the openings 7 provided corresponding to the explosion-proof valves V.

  The ventilation groove 81 has, for example, a U-shaped or U-shaped cross-sectional shape. FIG. 2 shows a ventilation groove 81 formed between the lower surface 64 of the resin 6 and the upper surface 42 of the heat sink 4.

  In the following description, the explosion-proof valve V arranged at the position of m rows and n columns is represented by “Vmn” (m = 1, 2, 3, n = 1, 2, 3).

  As shown in FIG. 4, a ventilation groove 81 is extended from the opening 7 on the explosion-proof valves Vm1 and Vm3 to the edge 65 on the lower surface. As a result, the explosion-proof valves Vm1 and Vm3 are vented to the outside air through the opening 7. Hereinafter, “venting the explosion-proof valve V to the outside air” means that the explosion-proof valve V is vented to the outside air through the opening 7. In the following description, when the ventilation groove 81 for venting the explosion-proof valve V and the ventilation of the explosion-proof valve V are described, the “venting groove 81 from the opening 7 on the explosion-proof valve V” will be referred to in order to simplify the description. The description may be made with the opening 7 omitted, such as “the ventilation groove 81 from the explosion-proof valve V”.

The ventilation groove 81 according to the present embodiment allows the explosion-proof valve Vm2 to vent to the outside air via the explosion-proof valves Vm1 and Vm3 adjacent to the explosion-proof valve Vm2. (For example, the explosion-proof valve V22 is vented to the outside air through the explosion-proof valves V21 and V23.) A ventilation groove 81 for venting the explosion-proof valve Vm2 extends from the explosion-proof valve Vm2 to both of the explosion-proof valves Vm1 and Vm3. However, it is only necessary to extend from the explosion-proof valve Vm2 to at least one of the explosion-proof valves Vm1 and Vm3.
Further, a ventilation groove 81 is extended from the explosion-proof valves V1n and V3n to the edge 65 on the lower surface, and the ventilation groove 81 is provided so that the explosion-proof valve V2n can vent the outside air via the explosion-proof valve V1n and / or the explosion-proof valve V3n. It may be provided.

  Here, as a comparative example, a ventilation groove 81 is provided from the opening 7 on the explosion-proof valve V22 to the edge 65 of the lower surface 64 in order to allow the explosion-proof valve V22 arranged at the position of 2 rows and 2 columns to vent to the outside air. The total length of the ventilation groove 81 for venting the explosion-proof valve V22 is longer than, for example, the total length of the ventilation groove 81 for venting the explosion-proof valve V21 from the opening 7 on the explosion-proof valve V22.

  In the present embodiment, the vent groove 81 for venting the explosion-proof valve V22 does not need to be extended to the edge 65 of the lower surface 64 as in the comparative example, so that the explosion-proof valve V22 is compared with the comparative example. The overall length of the ventilation groove 81 for ventilating the air is shortened, and the contact area between the resin 6 and the heat sink 4 is increased by the shortened length.

  Similarly, in this embodiment, a ventilation groove 81 for venting the explosion-proof valve V12 extends from the opening 7 on the explosion-proof valve V12 to the opening 7 on the explosion-proof valve V11 and the opening 7 on the explosion-proof valve V13. Further, a ventilation groove 81 for venting the explosion-proof valve V32 is extended from the explosion-proof valve V32 to the explosion-proof valve V31 and the explosion-proof valve V33.

  In FIG. 4, the ventilation groove 81 is extended from the explosion-proof valve V12 to the adjacent explosion-proof valves V11 and V13. However, when the distance from the explosion-proof valve V12 to the edge 65 of the lower surface 64 is shorter than the distance from the explosion-proof valve 12 to the adjacent explosion-proof valves V11 and V13, the ventilation groove 81 for venting the explosion-proof valve V12 is explosion-proof. You may extend from the valve V12 to the edge 65 of the lower surface 64. FIG. Similarly, in FIG. 4, the ventilation groove 81 is extended from the explosion-proof valve V32 to the explosion-proof valves V31 and V33 adjacent thereto. However, when the distance from the explosion-proof valve V32 to the edge 65 of the lower surface 64 is shorter than the distance from the explosion-proof valve 32 to the adjacent explosion-proof valves V31 and V33, the ventilation groove 81 for venting the explosion-proof valve V32 is explosion-proof. You may extend from the valve V32 to the edge 65 of the lower surface 64. FIG.

  According to the cooling structure of the electrolytic capacitor 5 according to the above embodiment, since the ventilation groove 81 for allowing the explosion-proof valve V to vent to the outside air is shortened, the contact area between the resin 6 and the heat sink 4 is reduced by the shortened amount. It becomes wide and can improve heat dissipation.

  In addition, the ventilation groove 81 for venting the explosion-proof valve Vm2 disposed at the center of the lower surface 64 is extended from the explosion-proof valve Vm2 to both of the explosion-proof valves Vm1 and Vm3 adjacent thereto, thereby improving the air permeability. Can be made.

  In addition, the resin pin 53 standing from the upper surface 62 and passing through the pilot hole of the substrate 3 is fixed with an adhesive or the like, whereby the resin 6 is fixed to the second region 32 of the substrate 3. The relative movement between the terminal 51 of the electrolytic capacitor 5 and the substrate 3 provided integrally with each other is restricted, and it is possible to prevent the terminal 51 of the electrolytic capacitor 5 from being broken by vibration and impact.

(Modification 1)
Next, a first modification of the electrolytic capacitor cooling structure 1 will be described with reference to FIG.
In the above embodiment, the ventilation groove 81 extends from the explosion-proof valve Vm2 disposed at the center of the lower surface 64 to at least one of the explosion-proof valves Vm1 and Vm3 disposed at the end of the lower surface 64, so that the explosion-proof valve Vm2 is provided. The air was vented to the outside air through the explosion-proof valves Vm1 and Vm3.

  On the other hand, the ventilation groove 81 according to the modified example 1 allows the explosion-proof valve V22 to vent to the outside air via the eight explosion-proof valves V as shown in FIG. That is, all nine explosion-proof valves V are connected in series by the ventilation groove 81. The nine ventilation grooves 81 and the nine explosion-proof valves V constitute one ventilation path 8.

  As described above, when all of the nine explosion-proof valves V are connected in series by the ventilation groove 81, the total length of the ventilation grooves 81 connecting the explosion-proof valves V is minimized. Thereby, the contact area of the resin 6 and the heat sink 4 becomes the maximum, and heat dissipation can be improved.

  In the first modification, as shown in FIG. 5, the explosion-proof valve V that directly ventilates the outside air is the explosion-proof valve V31. However, the present invention is not limited to this, for example, almost the entire length of the ventilation path 8. It is good also as the explosion-proof valve V13 located in the center. Thereby, even if it is the one ventilation path 8, it becomes possible to improve air permeability.

(Modification 2)
Next, a second modification of the electrolytic capacitor cooling structure 1 will be described with reference to FIG.
In the said embodiment and the modification 1, arrangement | positioning of the several explosion-proof valve V was demonstrated roughly with reference to FIGS. On the other hand, in the second modification, the arrangement of the plurality of explosion-proof valves V will be specifically described with reference to FIG.

  As shown in FIG. 6, 17 explosion-proof valves V are arranged on the lower surface 64 of the resin 6 so as to be adjacent to each other. FIG. 6 shows 15 explosion-proof valves Va arranged at a position where the distance to the edge 65 of the lower surface 64 is relatively close, and two pieces arranged at a position where the distance to the edge 65 of the lower surface 64 is relatively far. The explosion-proof valve Vb is shown.

  By extending the ventilation groove 81 from the explosion-proof valve Va to the edge 65 of the lower surface 64, the explosion-proof valve Va is directly vented to the outside air. On the other hand, by connecting the explosion-proof valve Vb and the adjacent explosion-proof valve Va by the ventilation groove 81, the explosion-proof valve Vb is indirectly ventilated to the outside air.

  As described above, when the explosion-proof valve Vb is vented to the outside air, the explosion-proof valve Vb and the explosion-proof valve Va may be connected by the ventilation groove 81, and the ventilation groove 81 extends from the explosion-proof valve Vb to the edge 65 of the lower surface 64. There is no need to let them. For this reason, the total length of the ventilation groove 81 for allowing the explosion-proof valve Vb to vent to the outside air is shortened, and the contact area between the resin 6 and the heat sink 4 can be increased by the shortened length.

(Modification 3)
Next, a third modification of the electrolytic capacitor cooling structure 1 will be described with reference to FIG.
In Modification 3, the arrangement of the 15 explosion-proof valves Va and the two explosion-proof valves Vb is the same as the arrangement shown in Modification 2.

  In the second modification, the explosion-proof valve Va arranged at a position where the distance to the edge 65 of the lower surface 64 is relatively close is directly vented to the outside air, and the distance to the edge 65 of the lower surface 64 is relatively far. The arranged explosion-proof valve Vb was indirectly ventilated to the outside air.

  On the other hand, in the modification 3, the ventilation groove 81 connects 15 explosion-proof valves Va and two explosion-proof valves Vb in series. Thus, one ventilation path 8 is configured by the 17 ventilation grooves 81 and the 17 explosion-proof valves Va and Vb.

  As described above, even when all of the 17 explosion-proof valves Va and Vb are connected in series with the ventilation groove 81, in order to improve heat dissipation, the total length of the ventilation groove 81 is shortened to reduce the resin 6 and The contact area with the heat sink 4 is increased.

  In the above-described embodiment and each modified example, the ventilation groove 81 in which a plurality of explosion-proof valves V are vented to the outside air through the other explosion-proof valves V is shown. However, the present invention is not limited thereto, and the plurality of explosion-proof valves. Ventilation groove 81 that allows at least one explosion-proof valve V of V to vent to the outside air through at least one other explosion-proof valve V may be used.

  In the above embodiment, the ventilation groove 81 for allowing the explosion-proof valve V to vent to the outside air is provided on the lower surface 64 of the resin 6. However, the present invention is not limited to this, and the ventilation groove 81 is provided on the upper surface 42 of the heat sink 4. It may be provided on both the lower surface 64 of the resin 6 and the upper surface 42 of the heat sink 4. Thereby, the freedom degree of design of the ventilation groove | channel 81 can be raised.

  In the above embodiment, in the electrolytic capacitor unit 2 provided with the opening 7 corresponding to the explosion-proof valve V, the ventilation groove 81 indirectly vents the explosion-proof valve V to the outside air through the opening 7. However, the present invention is not limited to this, and when the opening 7 is not provided in the electrolytic capacitor unit 2, the ventilation groove 81 may be configured to directly vent the explosion-proof valve V to the outside air.

  Furthermore, in the above embodiment, the electrolytic capacitor unit 2 in which the electrolytic capacitor 5 and the resin 6 are integrally formed has been described. However, the present invention is not limited thereto, and, for example, a plurality of electrolytic capacitors 5 are accommodated in a heat-dissipating resin. By applying the present invention also to the electrolytic capacitor unit 2 that has been made, the heat dissipation of the electrolytic capacitor 5 can be enhanced.

  In the above embodiment, the cooling structure having the electrolytic capacitor unit 2 and the heat sink 4 is shown. However, the present invention is not limited to this, and the electrolytic capacitor unit 2 alone without the heat sink 4 can be combined with the above embodiment. The same effect is produced. That is, a ventilation groove 81 for venting the explosion-proof valve V to the outside air is provided on the lower surface 64 (contact surface) of the resin 6, and the ventilation groove 81 is configured to be short so that the resin 6 and the heat radiation destination The contact area becomes larger and the heat dissipation can be improved.

  In addition, each of the above-described embodiments is merely an example of a specific example for carrying out the present invention, and the technical scope of the present invention should not be construed as being limited thereto. That is, the present invention can be implemented in various forms without departing from the gist or the main features thereof.

  INDUSTRIAL APPLICABILITY The present invention is suitably used for an electrolytic capacitor cooling structure and an electrolytic capacitor unit that need to improve heat dissipation.

V Explosion Proof Valve 1 Cooling Structure 2 Electrolytic Capacitor Unit 3 Substrate 4 Heat Sink 5 Electrolytic Capacitor 6 Resin 7 Opening 8 Ventilation Path 31 First Region 32 Second Region 81 Ventilation Groove

Claims (5)

A heat-dissipating resin having a first surface, a plurality of electrolytic capacitors provided integrally with the heat-dissipating resin, having an explosion-proof valve, and arranged with the explosion-proof valve on the first surface side;
An electrolytic capacitor unit comprising:
A heat dissipating member comprising a second surface and attached to the first surface in thermal contact with the second surface;
With
A ventilation path is provided on at least one of the first surface and the second surface to allow all of the plurality of explosion-proof valves to vent to the outside air,
The cooling structure for an electrolytic capacitor, wherein the ventilation path includes a ventilation groove that allows at least one explosion-proof valve of the plurality of explosion-proof valves to vent to the outside air through at least one other explosion-proof valve.   The electrolytic capacitor cooling structure according to claim 1, wherein the ventilation groove connects all of the plurality of explosion-proof valves in series. A substrate provided on a third surface opposite to the first surface in the heat-dissipating resin, and having a first region connected to a terminal of the electrolytic capacitor;
The cooling structure for an electrolytic capacitor according to claim 1, wherein a second region excluding the first region in the substrate is fixed to the third surface.   The electrolytic capacitor cooling structure according to any one of claims 1 to 3, wherein the electrolytic capacitor unit is formed by integrally molding the heat-dissipating resin and the electrolytic capacitor. A heat dissipating resin with a contact surface that is in thermal contact with the heat dissipating destination;
A plurality of capacitors provided integrally with the heat-dissipating resin, having an explosion-proof valve, and arranged on the contact surface side of the explosion-proof valve;
With
Provided on the contact surface a ventilation path for venting all of the plurality of explosion-proof valves to the outside air,
The electrolytic capacitor unit, wherein the ventilation path includes a ventilation groove that allows at least one explosion-proof valve of the plurality of explosion-proof valves to vent to the outside air through at least one other explosion-proof valve.

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